Drive arrangement for metering mechanisms

Abstract

A metering arrangement for powdered material, particularly powdered beverage ingredients, includes a storage container (18), an outfeed box (22) located beneath the storage container and having an outfeed opening (46), and a reciprocatingly movable outfeed slide (60). The outfeed slide and the outfeed box are embraced by a rubber band (78), for returning the outfeed slide. The outfeed slide co-acts with a motor (36) drivingly operating the slide (40) having an L-shaped cut-out (100) in which a slide driver (94) eccentrically mounted on the crankshaft (92) of the motor is intended to move. When dispensing a metered quantity of powder, the slide driver moves in the transverse leg of the L-shaped cut-out during a first half of a revolution so as to draw out the operating slide (40) and the outfeed slide (60). The slide driver then passes into the longitudinal leg of the L-shaped cut-out and releases its engagement with the operating slide (40), whereupon the outfeed slide (60) and the operating slide (40) are snapped back by the rubber band (78). The outfeed slide therewith strikes against the outfeed box (22) and generates a shock wave which shakes any arched or bridge-like incrustation present in the storage container (18).

I claim: 
     
       1. A metering arrangement for powdered material, particularly powdered beverage ingredients comprising a storage container (18), an outfeed box (22) located beneath the storage container and provided with an outfeed opening (46), and a reciprocating movable outfeed slide (60), having spring means for returning the outfeed slide, which is arranged to be displaced axially to an outfeed position against the spring force of the spring means and to be returned to its starting position in a snap-like manner by said spring means, characterized in that the aforesaid movements are effected by means of a drive mechanism (34) which includes a drive motor (36) having a crankshaft (92) which is oriented essentially at right angles to the plane of said movements and has an eccentrically located end (94) which functions as a slide driver and which is mounted in an essentially L-shaped cut-out (100) provided in an operating slide (40) activated by said spring force via the outfeed slide, said cut-out having a traverse leg or slot (102) which extends transversely to the displacement direction for conforming movement of the slide to the outfeed position, and having a longitudinal leg or slot (104) extending in the direction of slide displacement, for snap-like automatic return of the two slides (40 and 60) to the starting position. 
     
     
       2. A metering arrangement according to claim 1, characterized in that the outfeed opening (46) of the outfeed box (22) is partially closed at the top by a shelf (50) and is closed at the bottom by the bottom (52) of the outfeed box; in that the outfeed opening (46) accommodates the outfeed slide (60), which has essentially the shape of a bottomless box and comprises a front wall (62), side walls (64) and a dogging device (66) located between the rear ends of said walls; and in that the dogging device (66) has an angled cross-sectional shape presenting a gently and rearwardly sloping surface (70) and an essentially vertical front wall (72) for advancing a metered quantity of powder. 
     
     
       3. A metering arrangement according to claim 2, characterized in that the side walls (64) of the outfeed box (22) terminate in rear hook-like members for holding the box in the opening (46). 
     
     
       4. A metering arrangement according to claim 2, characterized in that the short sides of the front wall means for receiving a rubber band (78) which embraces the have opposed lugs (74), each lug having a pair of horizontally extending projections defining a recess therebetween, each recess forming front wall of the outfeed slide (60) and the outfeed box (22) and forms said spring means for returning the outfeed slide (60). 
     
     
       5. A metering arrangement according to claim 1, characterized in that the drive motor (36) has a motor attachment (38) of essentially box-shape and presenting at the top thereof a cross-strut (82) at the end thereof facing the outfeed slide, said cross-strut defining an opening (80) for the operating slide (40), and two shoulders (84) at the other end for holding the slide (40). 
     
     
       6. A metering arrangement according to claim 5, characterized in that the motor attachment (38) is provided at the bottom thereof with a bore (86), for the crankshaft (92), and holes for securing the drive motor (36) with the aid of screws, and a microswitch (88), having a breaker tongue (98), is arranged in an internal crankshaft space (90) of the motor attachment and the breaker tongue (98) of the microswitch is operated via a lifting cam (96) opposite the slide driver. 
     
     
       7. A metering arrangement according to claim 4, characterized in that the operating slide (40) has on the end thereof facing the outfeed box two hook-shaped projections (106) which engage behind the lugs (74) of the outfeed slide inwardly of the rubber band (78). 
     
     
       8. A metering arrangement according to claim 1, characterized in that the longitudinal leg (104) of the cut-out (100) is wider than the transverse leg (102) and said transverse leg has essentially the same width as the diameter of the slide driver, and an inner corner (110) joining the transverse and longitudinal legs has a smooth transition. 
     
     
       9. A metering arrangement according to claim 1, characterized in that the slide driver (94) is caused to stop, subsequent to the snap-like return movement, at a selected position within the longitudinal leg (104) by a control system means having components mounted on a circuit card in co-action with a microswitch (88), which has an input (112), a first output (114) and a second output (116). 
     
     
       10. A metering arrangement according to claim 9, characterized in that when the microswitch is opened current passes via the first output (114) directly to the drive motor (36), which then rotates at a high speed (6); when the microswitch is closed current passes through the second output (116) and a series resistance arranged on the circuit card and this slows down rotation of the and drive motor; when starting a new dispensing cycle the resistance can be by-passed in order to initiate a new metering cycle at full speed. 
     
     
       11. A metering arrangement according to claim 5, characterized in that the operating slide (40) has on an end thereof facing the outfeed box two hook-shaped projections which engage behind opposed lugs carried by the outfeed slide (60), the operating slide (40) has an upwardly projecting locking shoulder (108) which presents a sloping insertion surface which enables insertion of the operating slide (40) but prevents said slide from being withdrawn past the cross-strut (82) and the maximum length of stroke of the operating slide is limited in one direction by the hook-shaped projections (106) and in the other direction by the locking shoulder (108).